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Coordinating, Developing, and Delivering Highway Transportation Innovations

Overview

 

Research and Development (R&D) Project Sites

Project Information
Project ID:   FHWA-PROJ-12-0106
Project Name:   Splice Length of Prestressing Strand in Field-Cast Ultra-High Performance Concrete Connections
Project Status:   Completed
Start Date:  February 1, 2012
End Date:  January 31, 2014
Contact Information
Last Name:  Graybeal
First Name:  Benjamin A (Ben)
Telephone:  202-493-3122
E-mail:  benjamin.graybeal@dot.gov
Office:   Office of Infrastructure Research and Development
Team:   Bridge and Foundation Engineering Team [HRDI-40]
Program:   IRT (Infrastructure Research and Technology)
Laboratory:   Concrete Laboratory
Project detail
Roadmap/Focus area(s):   Infrastructure Research and Technology Strategic Plan and Roadmap
Project Description:   The development length of reinforcements embedded into ultra-high performance concrete (UHPC) can be significantly shorter than the lengths normally associated with conventional concrete. Shortening the development length of prestressing strand can allow for a redesign of some structural systems, including spliced girder and continuous-for-live-load bridges. Ultra-high performance concrete, when used in field-cast connections between prefabricated elements, can create robust connections that emulate monolithic components. This study investigated the development length of 12.7 and 15.2 mm diameter untensioned prestressing strands embedded in steel fiber and polyvinyl alcohol (PVA) fiber reinforced UHPC. The volumetric fiber content was 2 percent. A novel tension test method allowed for replication of the tension-tension stress state that could occur when strands are lap spliced within a connection between two linear elements. The results suggest that, for the steel fiber reinforced UHPC, the 12.7 mm diameter strands can be fully developed within 51 cm and the 15.2 mm diameter strands can be fully developed in approximately 61 cm. The 12.7 mm diameter strands can be fully developed in the PVA fiber reinforced UHPC in approximately 91 cm. Engaging UHPC to create lap splice connections of prestressing strands may allow for increased structural efficiency and increased structural redundancy through the use of simple, noncongested, nonpost-tensioned connection details.
Goals:  
The objective of this research study is to evaluate the lap splice length of untensioned prestressing strands embedded in field-cast ultra-high performance concrete (UHPC) connections. This research result is critical to the broader use of UHPC-class materials as field-cast grouts in connections between Prefabricated Bridge Elements and Systems (PBES) components. The research may allow for new connection designs and new structural configurations that enhance robustness and efficiency.
Product Type:   Article
Research report
Techbrief
Technical report
Test Methodology:   Complete mechanical tests to assess lap splice behavior with multiple strand sizes and ultra-high performance concrete fiber types. Analyze results in context of prior research on similar materials.
Expected Benefits:   This project will facilitate the broader use of ultra-high performance concrete-class materials, thus allowing for the construction of a more robust, durable highway infrastructure.
Deliverables: 1. Name: Splice Length of Prestressing Strand in Field-Cast Ultra-High Performance Concrete Connections
Product Type(s): Research report, Technical report
Description: Full report providing the results of the research.
2. Name: Splice Length of Prestressing Strand in Field-Cast Ultra-High Performance Concrete Connections
Product Type(s): Techbrief
Description: TechBrief. Executive Summary of the findings of the research.
Publication URL(s):
http://www.fhwa.dot.gov/publications/research/infrastructure/structures/hpc/14041/14041.pdf
3. Name: Splice Length of Prestressing Strand in Field-Cast Ultra-High Performance Concrete Connections
Product Type(s): Research report, Article
Description: Journal Manuscript: Materials and Structures
Related URL(s):   http://www.fhwa.dot.gov/research/resources/uhpc/
FHWA Topics:   Roads and Bridges--Construction and Project Management
TRT Terms:   Concrete Structures
Infrastructure
Bridges
Prefabricated Bridges
Concrete
Research
Grout
FHWA Disciplines:   Construction and Project Management
Design
Structures
Pavement and Materials
Subject Areas:   Bridges and other structures
Materials
Research
Construction

 

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